The present invention relates to a device for working the ground comprising a frame with a plurality of standing shafts mounted pivotally thereon, each of which is provided on a free end with a lying shaft whereon a disc-shaped body is rotatably mounted, wherein each disc-shaped body has a concave and a convex side. Such a device is known from the U.S. Pat. No. 3,675,725.
Such a device (normally known as a disc harrow) is used in agriculture for further working of ploughed earth, for ploughing under seed and manure and/or for weed control. It is of great importance in these workings to keep the working depth, i.e. the depth to which the discs work the ground, substantially unchanged. A disc harrow is generally fixed for this purpose to a so-called three-point lifting device that forms part of a tractor and with which the position of the harrow relative to the tractor, and therewith the working depth is controlled.